Fuel injection pump



Aug. 16, 1938. H. c. EDWARDS 2,127,211

FUEL INJECTION PUMP Filed March 25, 1936 2 Shets-Sheet l www w/ML, 7 2 h Wl Patented Aug. 16, 1938 UNITED STATES FUEL INJECTION PUMP 'Herbert c. Edwards, Massillon, omo, assigner to The Timken Roller Bearing Company, Canton, Ohio, a corporation of 0h10 Application March 25, 1936, Serial No. 70,804

6 Claims.

This invention relates to fuel injection pumps of the kind having a plurality of reciprocating pistons that are rotated in their respective cylinders by means of a single rack to regulate the quantity of fuel delivered. The invention has for its principal objects to provide the piston-turning rack with means for independently adjusting the angular position of each piston so as to obtain a proper initial setting thereof, to provide a simple stop mechanism for said rack that can be readily adjusted to limit the maximum quantity of fuel delivered, and td provide for simplicity and cheapness of construction and compactness of design. The invention consists in the construction, combinations and arrangements of parts hereinafter described and claimed. In the accompanying drawings, which form part of this specification and lwherein like symbols refer to like parts wherever they occur,

Fig. 1 is a side elevation of an injection pump embodying my invention,

Fig. 2 is a horizontal section on the line 2-2 in Fig. l,

Fig. 3 is a section similar to larged scale,

Fig. 4 is a vertical transverse section through the pumpthe section being taken through one of the pump cylinders on the line 4-4 in Fig. 1,

Fig. 5 is a section similar to Fig. 4, the section being taken through the lower portion of the cylinder at right angles to the section shown in Fig. 4,

Fig. 6 is a longitudinal section through the control rod stop mechanism on the line 6--6 in Fig. 3,

Fig. 7 is a transverse section on the line 1-1 in Fig. 3,

Fig. 8 is a side elevation of the control rod; and

Fig. 9 is a cross-section through said rod on the line 9 9 in Fig. 8.

In the accompanying drawings, my invention is shown in connection with a multi-cylinder fuel injection pump comprising a suitable housing I provided with a plurality of vertical bores 2 that are spaced apart longitudinally of said housing and have enlarged lower end portions adapted to slidably receive tappet cups 3 that are engaged at their lower ends by cams or tappets 4 on a cam shaft 5 located in the longitudinal chamber in the bottom of the pump housing. Mounted in each of the vertical bores 2 in the pump housing i is a pump cylinder 1, which contains a, piston or plunger 8 and has an enlarged upper end portion 9 that is held down on an annular seat I0 provided therefor in the upper portion of said bore Fig. 2 on an enby means of a tubular member II. The member rests on the upper end of the pump cylinder 'I and is provided at its upper end with a seat for a suitable fuel discharge valve I2. Threaded into the upper end of the bore 2 is a tubular tting or shell I3, which holds the valve seat member II down on the upper end of the pump cylinder and is provided at its upper end with a space for a coll spring i4 that normally holds the fuel discharge valve i2 against the seat provided therefor at the upper end of said member. A fuel discharge pipe i5 has a conical end portion seated in a beveled seat provided therefor in vne upper y Cl end of the tubular tting or shell I3 and is held in position by means of a cap I6 threaded on the upper end of said uiting.

The pump housing is provided on one side oi' the cylinders therein with a longitudinal passageway il, which receives liquid fuel from a suitable feed pump (not shown) and communicates with an inlet port i@ in the wall of each cylinder. Said housing is also provided on the opposite side of said cylinders with a. longitudinal overilow passageway l@ that communicates with an overow port 2li located in each cylinder opposite the inlet port I8 therein. Each piston 8 is of the general type provided with an annular groove 2I that communicates through a longitudinal pe-v ripheral groove 22 with the pressure space 23 above the piston and has an inclined or helical upper edge 24, whereby .the effective delivery stroke oi the piston may be regulated by turning the pistonin its cylinder to vary the point in the delivery stroke of the piston in which the overflow port 2Il is placed in communication with said pressure space through the grooves 2| and 22. By, this arrangement, delivery of the fuel begins as soon as the piston on its way up covers the ports I1 and I8 and ends as soon as the helical upper edge 24 of the annuluar groove 2| in the piston opens the overflow or' by-pass port 20 and relieves the pressure in the space above said piston.

The mechanism for turning the pistons on their axes to vary the amount of fuel delivered thereby comprises axially alined upper and lower driving and driven sleeves 25 and 26 mounted on the lower end portions of the cylinders and pistons, respectively, and a rack rod 21 mounted in a horizontal bore 28 that extends longitudinally of the pump housing from end to end thereof on one side of the cylinders and cooperates vwith gears 29 on the upper ends 'of the driving sleeves. The upper or driving sleeve 25 for each piston is rotatably mounted on the lower end of the cyl- 2 inder therefor: and the lower or driven sleeve 29 has a non-rotatable connection with the lower end of said piston comprising a flat sided portion 39 on the piston that fits a similarly shaped opening in the lower end of said lower sleeve. 'Ihe driving connection between the driving sleeve 25 and the driven sleeve 29 preferably comprises upwardly extending diametrically opposed tongues 3| on the driven sleeve that fit within downwardly opening diametrically opposed notches 32 provided therefor in the driving sleeve,

. to hold the driving sleeve upwardly in the tappet cup receiving portion of the vertical bore in the pump housing. 'I'he tappet cup l surrounds the driven sleeve 2l, but is spaced therefrom far enough to accommodate the piston reti-acting spring 33. A washer 35 supports the driving sleeve 25 below the gear 29 thereon and is held against an annular shoulder 2l provided therefor in the vertical housing bore by means of the spring 33. The piston is provided below the bottom or lower portion of the driven sleeve 29 with an annular groove." and terminates below said groove in a flatsided head portion I9. The lower end of the piston retracting spring 33 is supported upon an annuluar seat provided therefor on a member 39 having a lateral notch 49 therein whose upper portion snugly receives the grooved portion 21. of the piston and whose lower portion is widened to receive the head 39 at the lower end of said piston. "Ihus, the spring seat member I9 is held against axial movement relative to the piston. but may be rotated relative thereto and removed sidewise therefrom.

Thebottom wall of the lower or driven sleeve 29 on each piston fits between the upper end of the spring seat member 39 thereon and a collar 4l formed integral therewith, thereby preventing relative axial movement of said sleeve and said piston. The tappet cup l is adjusted vertically by means of a block 42, which is slidably supported in an undercut cross slideway 4l provided therefor in the bottom of the spring seat member 39. The adjusting block is inserted in and removed from the slideway 49 in the spring seat 99 through an opening r44 provided therefor in the side wall gf the tappet cup 3, said block being provided with a threaded bore 45 adapted to be engaged by a threaded pin (not shown) for inserting and removing it through said opening. As shown in Fig. 4. the adiusting block has a raised middle portion 42a that fits within the lower end of the spring 33, thereby retaining said block in the slideway 43 provided therefor in the spring seat 39.

As shown in the drawings, the rack or control rod 21 has a loose fit in the longitudinal bore 29 provided therefor in the pump housing and extends beyond the ends of said housing. The forward end 4l of the rack rod is adapted for connection with a suitable mechanism (not shown) for reciprocating the rod in the housing, no fuel being delivered by the pump when said rod is at one end of its reciprocating movement and a maximum quantity of fuel being delivered when said rod is at the other end of said movement. The rack rod is slidably supported in the forward end of the housing bore 28 by means of a bushing 28a threaded therein. A cylindrical casing 41 has 4threaded plug 6| a reduced end portion 48, which is threaded into the other end of said bore and slidably supports said rack rod. This cylindrical casing contains and forms part of va device that limits the rearward travel of the rack rod and thus controls the maximurr quantity of fuel delivered by the pump.

Mounted in the casing 41 for longitudinal sliding but non-rotary movement therein is a stop bar 49 that is disposed crosswise of said casing with its Aends supported in diametrically opposed longitudinal slots 59 cut in the cylindrical wall thereof. The stop bar or member 49 is adapted to be directly engaged by the adjacent end of the rack rod 21 or by a plug 5I that seats within an axial recess provided therefor in said end of said rack rod. The ends of said stop bar are provided with threads adapted to cooperate with the internal thread of an externally knurled sleeve 52 that is rotatably mounted on the cylindrical casing 41 of the rack rod stop device between the adjacent end wall of the pump housing and an annular shoulder formed on said casing adjacent to the outer end thereof, which is shaped to receive a wrench. By this arrangement, the stop bar 49 may be adjusted longitudinally of the casing 41 to vary the rearward travel of the rack rod andthus regulate the maximum quantity of fuel delivered by rotating the knurled sleeve 52,which, due to its threaded connection with said stop bar, causes the latter to move longitudinally of the guide slots 50 providedtherei'or in said casing. 'I'he adjusting sleeve 52 may be locked in the de l sired positionof its rotary adjustment by means of a cotter pin 53 that extends through registering openings provided therefor in the outer end portion of the sleeve and the removable casing or holder.

The rack rod is provided with a series of longitudinal detachable rack sections or blocks 54 adapted to intermesh with the gears 29 of the respective metering or driving sleeves 25. Each of the rack sections 54 is slidably mounted in a 1ongitudinal slideway 55 provided therefor in the cylinder opposing side of the rack rod, said slot being undercut and said rack sections having top and bottom ribs or flanges 56 that fit the undercut portions of said slot to prevent sidewise removal of said sections from said rod. Each of the rack sections 54 is adjusted longitudinally of the rack rod and is locked in adjustment position preferably by means of two horizontally spaced parallel screws 51 that are threaded into said rod transversely thereof and have conical end portions 58 adapted to engage horizontally spaced conical recesses 59 provided therefor in the rack rod of said rack section. The space between the two screws 51 is less than the space between the two recesses 59 engaged thereby, whereby the rack section is shifted longitudinally of the rack rod when one of said screws is tightened and is shifted in the opposite direction when the other screw is tightened. When one of the screws is tightened, the other is loosened to`permit the sliding movement imparted to the rack section by the first mentioned screw; and when both screws are tightened, the rack section is locked to the rack rod. The rear wall of the pump housing I is provided opposite the outer or rear ends of each pair of adjusting screws 51 with an opening 60 through which a suitable tool may be inserted to turn said screws, said'opening being closed by means of a The teeth of the endmost rack sections terminate short of the outer ends thereof, leaving plain end portions that are long enough to prevent the endmost gears from running out of mesh with said rack teeth, thereby limiting endwise movement of the rack rod in both directions.

The hereinbefore described piston rotating mechanism has numerous advantages. The toothed rack rod sections may be quickly and easily removed and replaced when worn or damaged; and said sections may be adjusted longitudinally of the rack rod independently of each other to obtain a uniform angular adjustment of all of the pump pistons without removing the rack bar 4or dismantling the pump. The stop mechanism for the rack rod is of simple, economical and compact construction; it may be quickly and easily adjusted to control the maximum quantity of fuel delivered and locked in the desired position of adjustment; and it is also adapted to be mounted on and dismounted from the pump housing as a complete unit.

The above described tappet adjusting mechanism is not claimed herein, being the subject matter of a separate application Serial No. 70,805, filed concurrently with this application.

What I claim is:

1. A fuel injection pump comprising a housing, a piston reciprocable therein, and means for turning said piston on its axis to vary its angular position, said means comprising a member slidable in said housing transversely of the piston axis, a rack removably mounted on said member and operatively connected to said piston to turn the same, and means for adjusting said rack relative to said member in the direction of the sliding movement thereof and for locking said rack to said member in the desired adjusted position, said last mentioned means comprising two screws threaded into said member and spaced apart in the direction of its sliding movement and having tapered ends adapted to engage tapered recesses provided therefor in said rack, the spacing of said screws differing from the spacing of said recesses.

2. A fuel injection pump comprising a housing, a piston reciprocable therein, and means for turning said piston on its axis to vary its angular position, said means comprising a member slidable in said housing transversely of the piston axis, a rack removably mounted on said member for sliding movement longitudinallythereof and operatively connected to said piston to turn the same, and means for adjusting said rack relative to said member in the direction of the sliding movement thereof and for locking said rack to said member in the desired adjusted position,

said last mentioned means comprising two screws" threaded into said member and spaced apart in the'direction of its sliding movement and having tapered ends adapted to engage tapered recesses provided therefor in said rack, the spacing of said screws differing from the spacing of said recesses, said housing being provided withv an opening through which access may be had to s aid screws, and a removable closure for said opening.

3. A fuel injection pump comprising a housing, l a plurality of pistons reciprocable therein, andv means for turning said pistons on their axes to vary the angular position thereof, said means comprising a rod axially slidable in said housing transversely of the piston axes, longitudinally spaced separate rack sections removably mounted on said rod and operatively connected to the respective pistons to turn the same, and means for independently adjusting each of said rack sections longitudinally of said rod and for locking said rack section in the desired adjusted position, said lastrmentioned means comprising two screws threaded into said rod and spaced apart longitudinally thereof and having conical ends adapted to engage conical recesses provided therefor in said rack sections, the spacing of said screws differing from the spacing of said recesses.

4. A fuel injection pump comprising a housing, a plurality of pistons reciprocable therein, and means for turning said pistons on their axes to vary the angular position thereof, said means comprising a rod axially slidable in said housing transversely of the piston axes and provided with a longitudinal undercut slide way, and separate rack sections slidably mounted in said slide way andoperatively connected to the respective pistons to turn the same, and means for independently adjusting each of said rack sections longitudinally of said slideway and for locking said lrack section in the desired adjusted position, said last mentioned means comprising two screws threaded into said rod through the bottom of said slideway and spaced apart longitudinally thereof and having conical ends adapted to engage conical recesses provided therefor in the slideway bottom opposing face of said rack section, the spacing of said screws differing from the spacing of said rece'sses.

5. A fuel injection pump comprising a housing, a plurality of pistons reciprocable therein, and means for turning said pistons on their axes to vary the angular position thereof, said means comprising a rod axially slidable in said housing transversely of the piston axes, and separate rack sections removably mounted on said rod and operatively connected to the respective pistons to turn the same, and means for independently 'tons of a multicylinder fuel injection pump comi prising a rod provided with azlongitudinai undercut slideway, a plurality of longitudinally spaced rack sections slidably mounted-in said slideway,y andmeans for independently-adjusting each of said rack sections longitudinally of said slideway and-forlocking said rack section in the desired vadjusted position, s aid adjusting and locking ,means'comprising two screws'threaded into said `rod' through the bottom of said slideway and y-spaced apart ylongitudinally thereof and having conical ends adapted to engage conical recesses provided therefor in the yopposing face of said rack section, the spacing of said screws diering fromthe spacing of said recesses.

HERBERT C. EDWARDS. 

